1. Technical Field of the Invention
The present invention relates to an apparatus for cleaning (washing) and subsequently drying an object of treatment and a method of cleaning and drying the object. More in detail, it relates to the cleaning and drying apparatus for cleaning and subsequently drying objects of treatment, for example, semiconductor wafers, LCD glass substrates, etc. and also relates to the cleaning and drying method for the objects.
2. Description of the Related Art
In the general manufacturing process for the semiconductor devices, it is carried out to successively load the substrates, such as the semiconductor wafers or the LCD glass substrates, in a processing bath having a cleaning liquid, such as a chemical liquid or a rinsing liquid, and further perform the cleaning process, for example, the chemical treatment, the rinsing process, etc. in the processing bath. Thereafter, it is further carried out to eject dry gas against the substrates in order to eliminate moisture clinging to the substrates in the drying process.
In the above-mentioned manufacturing process, hydrogen fluoride (HF) is employed as the chemical liquid in order to eliminate natural oxidation films on the substrates. In the HF cleaning, however, the resultant substrate"" surfaces are further activated, so that the contact of the substrates with air causes the natural oxidation films to be produced easily and also facilitates particle"" sticking to the surfaces of the substrates. Therefore, it has been conventionally executed to dry the substrates (after the cleaning process) in an atmosphere of inert gas, for example, nitrogen (N2) gas in order to make a situation being hard to form the oxidation films. However, if the substrates after the cleaning process are left in the air for a long time, then there are caused problems that the natural oxidation films are formed. on the surfaces of the substrates and the particles adhere to the surfaces.
Under the situation, it is recently adopted to positively form an protective oxidation film as one projection layer on each surface of the substrates in order to avoid the formation of the above natural oxidation film. As one method of forming the protective oxidation films positively, it is well known to dip the substrates in an ozone water to form the protective oxidation films thereon. As the method of producing the ozone water, there are known {circle around (1)} one method consisting of a step of passing oxygen between discharge electrodes thereby producing an ozone gas by the oxygen""s discharging energy and a sequent step of dissolving the resultant ozone gas in a demineralized water (pure water) through an osmosis membrane or the like, thereby producing the ozone water; and {circle around (2)} another method consisting of a step of electrolyzing the pure water thereby directly producing both ozone gas and hydrogen gas and a sequent step of dissolving the resultant ozone gas in the pure water.
In the former method {circle around (1)}, however, there are problems that an ozone water generating unit is large-sized and its running cost is large due to the use of oxygen gas as the raw material. Additionally, because of its structure that the gas passes through the discharging electrodes directly, the particle as the result of discharging the electrodes are included in the gas and further dissolved in the pure water, so that the particles exist in the produced ozone water.
On the contrary, according to the latter method {circle around (2)} of electrolyzing the pure water, it takes a lot of time to generate the ozone water although the apparatus is small-sized. Furthermore, due to the generation of hydrogen gas as a by-product, the method does not only require a great deal of time in exhausting the hydrogen gas, but cause a problem in safety.
Accordingly, it is an object of the present invention to provide a cleaning and drying apparatus which is small-sized and capable of easily generating the ozone water without generating particles, hydrogen gas, etc. thereby forming the oxidation film on the object after washing and before drying. It is another object to provide a cleaning and drying method for an object.
The first feature of the invention resides in that the cleaning and drying apparatus for the object to be treated comprising: a cleaning chamber defined by a processing bath storing a chemical liquid or a rinsing liquid, for washing the object therein; a drying chamber enclosed with a container, for drying the object; a rinse source for supplying rinsing liquid to the processing bath; a rinse supplying pipeline connecting the rinse source with the processing bath; an ozone water generating mechanism provided on the rinse supplying pipeline.
With the constitution mentioned above, it is possible to change the rinsing liquid flowing in the rinsing liquid pipeline to the ozone water by the ozone wafer generating unit and also possible to supply the processing bath with the resultant ozone water. Further, it is possible to form the protective oxidation film on the substrate by dipping it in the ozone water. Accordingly, since the protective oxidation film is formed on the substrate after completing the chemical treatment, the subsequent drying allows preventing the formation of natural oxidation film on the substrate and also the adhering of particles to the substrate.
The second feature of the invention resides in a chemical source for supplying chemical liquid to the processing bath and a chemical supplying pipeline connecting the chemical source with the processing bath, wherein the chemical supplying pipeline is joined to the rinse supplying pipeline so as to supply the processing bath with either the mixture consisting of the chemical and the rinsing liquid or the rinsing liquid selectively.
The above-mentioned structure allows the chemical liquid line, the rinsing liquid line and the ozone water line to be united for piping, thereby attaining the miniaturization of the apparatus.
The third feature of the invention resides in that the ozone water generating mechanism is located in the rinse supplying pipeline between the rinse source and a junction where the chemical supplying pipeline is joined to the rinse supplying pipeline.
The fourth feature of the invention resides in a flow switching valve provided on the rinse supplying pipeline between the rinse source and the ozone water generating mechanism, the flow switching valve having a first position, a second position and a third position, the first position of the valve giving large quantity of flow when only pure water is provided to the processing bath in a process of rinsing, the second position of the valve giving medium quantity of flow when HF is provided to the processing bath in a process of eliminating natural oxidation film, the third position of the valve giving small quantity of flow when ozone water is provided to the processing bath in a process of forming an protective oxidation film.
The fifth feature of the invention resides in that the container enclosing the drying chamber having a cover covering an upper space of the processing bath and being provided on the processing bath detachably.
The sixth feature of the invention resides in that the container has a plurality of exhaust ports formed in the periphery of a lower part thereof, for discharging gas supplied into the drying chamber.
With the above-mentioned structure, it is possible to spread the supplied dry gas all over the drying chamber and subsequently discharge the dry gas quickly.
The seventh feature of the invention resides in that the ozone water generating mechanism is activated when forming protective oxidation film on the surface of the object, not activated when a process of rinsing by pure water or a process of eliminating natural oxidation film by HF.
Thus, the rinsing liquid can be used in both of the rinsing process and the oxidation film formation process.
The eighth feature of the invention resides in a temperature regulating mechanism provided on the rinse supplying pipeline between the rinse source and the ozone water generating mechanism for regulating temperature of the rinsing liquid.
With the constitution, it is possible to provide the rinsing process and the oxidation film forming process with the rinsing liquid or the ozone water supplied to the processing bath and also adjusted at a designated temperature.
The ninth feature of the invention resides in that the temperature regulating mechanism is activated and controls predetermined temperature of hot ozone water, hot pure water and hot HF respectively, where a processing liquid is needed to be higher temperature than normal temperature such as when forming a protective oxidation film with hot ozone water, when rinsing the object with hot pure water and when eliminating natural oxidation film with hot HF.
Therefore, it is possible to provide the rinsing process and the oxidation film forming process with the rinsing liquid or the ozone water flowing in the pipeline for the rinsing liquid, which is adjusted at a designated temperature as occasion demands.
The tenth feature of the invention resides in that the cleaning and drying apparatus further comprises a magnetic field generating unit interposed in the pipeline for the rinsing liquid, on the upstream side of the ozone water generating unit.
With the constitution mentioned above, when the rinsing liquid in the pipeline for the rinsing liquid passes through the magnetic field produced by the magnetic field generating unit, the rinsing liquid is subjected to magnetism. Consequently, the bonding angles of molecules of the rinsing liquid can be uniformed thereby improving the producing efficiency of the ozone water.
The 11th feature of the invention resides in that pure water is employed as the rinsing liquid, the ozone water generating mechanism has a transparent pipe through which pure water passes and an ultraviolet lamp irradiating the pure water in the transparent pipe with ultraviolet rays.
With the constitution mentioned above, it is possible to produce the ozone water by irradiating the ultraviolet rays on the pure water flowing in the pipeline for the rinsing liquid.
The 12th feature of the invention resides in that the ultraviolet lamp is surrounded by the transparent pipe in central part of the transparent pipe.
The 13th feature of the invention resides in that the cleaning and drying apparatus further comprises a dry gas source communicated with the drying chamber through a dry gas pipeline.
With the constitution mentioned above, it is possible to supply the dry gas to the object after the chemical treatment, the rinsing process and the oxidation film forming process, thereby drying the object.
The 14th feature of the invention resides in that the cleaning and drying further comprises a heating unit interposed in the dry gas pipeline. Accordingly, since the dry gas of high temperature is supplied to the object, it is possible to improve the drying efficiency of the object.
The 15th feature of the invention resides in a cleaning and drying apparatus for an object of treatment, comprising: a cleaning chamber defined by a processing bath storing a chemical liquid or a rinsing liquid, for washing the object therein; a drying chamber enclosed with a container, for drying the object; a chemical source. supplying chemical liquid to the processing bath; a rinse source supplying rinsing liquid to the processing bath; a rinse supplying pipeline connecting the rinse source with the processing bath; an ozone water generating mechanism provided on the rinse supply pipeline for producing ozone water; a temperature regulating mechanism provided on the rinse supplying pipeline between the ozone water generating mechamism and the rinse source, for adjusting temperature of pure water supplied to the ozone water generating mechanism; a magnetic field generating mechanism provided on the rinse supplying pipeline between the ozone water generating mechanism and the rinse source, for applying magnetic field on the pure water supplied to the ozone water generating mechanism; and a controler for controlling the operations of the ozone water generating mechanism, the temperature regulating mechanism and the magnetic field generating mechanism.
The 16th feature of the invention resides in that the controler is operable of the operations of the ozone water generating mechanism, the temperature regulating mechanism and the magnetic field generating mechanism, selectively.
With the above constitution, the apparatus is capable of complying with a variety of cleaning/drying conditions, thereby accomplishing the most suitable treatment and the automated treatment.
The 17th feature of the invention resides in a cleaning and drying method for an object to be treated, comprising the steps of: dipping the object to be treated in a chemical liquid thereby washing the object; dipping the object in a rinsing liquid thereby rinsing the object; dipping the object in an ozone water thereby forming an oxidation film on the surface of the object; and supplying the object having the oxidation film with dry gas thereby drying the, object.
The 18th feature of the invention resides in that in the step of rinsing the object or the step of forming the oxidation film of the object, it is executed to supply the rinsing liquid or the ozone water each adjusted at a predetermined temperature.
The 19th feature of the invention resides in that in the step of forming the oxidation film on the surface of the object, it is executed to use pure water as the rinsing liquid and also use the ozone water resulting from irradiating ultraviolet rays on the pure water.
The 20th feature of the invention resides in that it is executed to apply magnetic field on the pure water before generating the ozone water.
The above and other features and advantages of this invention will become apparent, and the invention itself will best be understood, from a study of the following description and appended claims, with reference had to the attached drawings showing one preferred embodiment of the invention.